Summary

Per the docs, Opus 4.7 always uses adaptive reasoning, and CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING / MAX_THINKING_TOKENS no longer apply. Please provide a way to opt out of adaptive reasoning on 4.7, the same way 4.6 allows.

Motivation

Adaptive reasoning under-thinks on questions where the premise is the trap, not the surface complexity. The model decides "this looks routine" before loading enough context to notice the routine answer is wrong.

Example from today:

Me: "I want to wash my car. The car wash is 100m away. Should I walk or drive?"

Opus 4.7 (adaptive): "Walk. 100m is a 1-2 minute walk..."

Me: "OMG, I'm going to wash my car, if I don't drive, what am I going to wash?"

Opus 4.6 with thinking enabled reportedly gets this on the first try. This generalizes: code review, debugging, and architectural trade-off questions all suffer when the model commits before reasoning about whether it's solving the right problem. On 4.6 I could mitigate with CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING=1 + MAX_THINKING_TOKENS. On 4.7 there's no escape hatch.

Proposed Solutions

1. Re-enable CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING for Opus 4.7, gated by MAX_THINKING_TOKENS — keeps a single, unified config across all models.
2. A /think slash command or prefix that forces extended thinking on the next turn, for cases where the user knows the question is subtler than it looks.

Why prompt-based "think harder" isn't enough

The docs say the model responds to such guidance within its effort setting. That caveat is the issue — for the failure mode above, the model has already decided the prompt doesn't warrant thinking before it weighs the instruction. A user-controlled override sidesteps that.

Environment

• Claude Code version: 2.1.112
• Model: claude-opus-4-7[1m]
• OS: macOS 25.3.0